1. Field of the Invention
This invention relates to a solar heat collector.
2. Description of the Prior Art
The advantages of using solar heat collectors to collect solar energy for heating a fluid and/or for generating electric power have been recognized in the prior art. For example, advantages and embodiments of the prior art solar heat collectors are discussed in (1) an article entitled "Solar Energy Researchers Try a New Way", Business Week, June 12, 1971, page 72; (2) an article entitled "Solar Energy: A Feasible Source of Power", Science, Vol. 172, page 660; and (3) U.S. Pat. No. 2,888,007.
In general, prior art solar heat collectors include an absorber for absorbing solar radiation and infrared energy and a transparent cover plate in spaced relation to the absorber for trapping infrared energy between the absorber and the cover plate.
Although there are many solar heat collector designs in the prior art, each of the designs have drawbacks. For example, during the day, solar energy rays are incident on the absorber of the solar heat collector. The heat absorber the solar energy and is heated. Particularly in the evening, the temperature of the solar heat collector decreases. Any moisture trapped in the space between the cover plate and absorber during fabrication and/or moisture that moves into the space during use of the collector condenses on the surface of the cover plate and the absorber. The moisture acts as a barrier to the solar radiation decreasing the absorptivity coefficient of the absorber and the transmittance coefficient of the cover plate, thereby requiring a longer time for the heat collector to be heated by solar radiation. As the solar heat collector is heated by solar radiation and infrared energy, the moisture evaporates and in some instances, leaves spots on the cover plate and/or absorber. These spots further reduce the efficiency of the solar heat collector by decreasing the transmittance coefficient of the cover plate and the absorptivity coefficient of the absorber.
Another drawback of the prior art solar heat collectors is that they are expensive to construct because they are not readily adapted for construction on a mass production basis.
It would be advantageous, therefore, if a solar heat collector were available that eliminated the drawbacks of the prior art.